摘要
嫦娥三号(CE-3)探测器成功实现了我国首次月球软着陆,对巡视器和着陆器进行高精度定位是保障两器顺利完成月面探测任务的必要前提.本文首先对CE-3月面工作段的测量方式、各观测量测量模型以及运动学统计相对定位方法进行讨论.其次对着陆器进行定位并对定位精度进行评价,得到着陆器坐标为:44.1206°N,-19.5124°E,高程-2632 m(相对1737.4 km月面),通过与月面数字高程模型以及NASA探测器LRO的航拍结果比较,定位差异优于50 m,分析表明VLBI数据对提高着陆器定位精度有显著贡献.最后,利用同波束VLBI数据进行月面巡视器与着陆器的相对定位.与视觉定位方法相比,本文所用的基于地基观测量的运动学统计定位法不受着陆器可视范围限制,且定位精度不随两器距离增加而降低.计算结果表明,在现有的测量条件下,使用纳秒量级的VLBI差分群时延数据,两器相对定位精度在百米;使用皮秒量级的VLBI差分相时延数据,并在定位过程中进行模糊度解算,可以实现米级的月面双目标的相对定位,具有重要意义.
The Chinese first lunar lander, Chang＇E-3, performed a lunar soft-landing on 14 Dec, 2013. Precise positioning for the lander and rover was the most important precondition and guarantee for a successful lunar surface exploration. In this study, first, the tracking system, measurement models and positioning method are discussed in detail. Second, the location of the CE-3 lander was determined： 44.1206°N, -19.5124°E, -2632 m（altitude was relative to the assumed lunar surface with a height of 1737.4 km）, and the analysis showed the VLBI（Very Long Base Interferometry） data were able to significantly improve the positioning accuracy. Furthermore, the positioning error was evaluated in various ways; the result was better than 50 m. Finally, the relative positioning of the rover and lander using earth-based observations was studied and compared with the optical positioning method using photographs taken by the lander and rover. The method applied in this study was not limited by the visible range of the lander, and the relative positioning accuracy did not decrease as the distance between the lander and rover increased. The results indicated that under the current tracking and measuring conditions, the relative positioning accuracy was about 100 m using the same beam VLBI group delay data with anosecond level noise. Furthermore, using the same beam VLBI phase delay data with picosecond level noise it was possible to significantly improve the relative positioning accuracy to the order of 1 m.
出处
《科学通报》
EI
CAS
CSCD
北大核心
2014年第32期3162-3173,共12页
Chinese Science Bulletin
基金
国家自然科学基金(11073047
11173052)
国家高技术研究发展计划(2012AA121603)
上海市科学技术委员会(12DZ2273300)
中国科学院行星科学实验室和探月工程资助
作者简介
联系人，E-mail：pjli@shao．ac．cn
联系人，E—mail：yongh@shao．ac．cn
